Vehicle restraints are well known in the art, and serve the vital safety function of preventing trucks and the like parked at a loading dock from separating from the dock during the loading or unloading of the vehicle. In the absence of a vehicle restraint, or if a vehicle restraint malfunctions, the vehicle may uncontrollably separate from the dock, leaving a gap between the vehicle and the dock and/or dockleveler disposed therein. As used herein "uncontrolled" separation refers to the situation where a truck separates from the dock at a time when such separation is undesired--such as when loading or unloading of the truck is occurring and/or when a vehicle restraint is engaged. For an uncontrolled separation, a fork truck operator (or other personnel or equipment) either approaching the rear of the truck or leaving the rear of the truck could fail to realize the presence of the gap with dire consequences--the worst being the fork truck falling from the loading dock or the truck to the driveway below. Indeed, several such accidents led, in part, to the innovation of the vehicle restraint itself.
While vehicle restraints fall into several general categories, the most prevalent category is ICC bar restraints. Such restraints are typically mounted on or adjacent to the dock face and include a hook or restraining member which engages the rear impact guard or "ICC bar" of the vehicle to prevent uncontrolled separation. The National Highway Transportation Safety Administration (NHTSA) recently promulgated new regulations for ICC bars, to take effect in 1998 (although truck manufacturers are already beginning to provide ICC bars that conform to the new regulations). Under these regulations, the ICC bars must be at least 4 inches in height, and meet other requirements for strength and deflection response to applied forces. For an ICC bar restraint to effectively perform the important function of preventing uncontrolled separation, it must be capable of restraining ICC bars conforming to the new standards.
One style of ICC bar restraint is that disclosed in U.S. Pat. No. 4,865,508 to Carlson, and commercially embodied in a vehicle restraint sold by the Kelley Company, Inc. of Milwaukee, Wis. under the model name "Star." A Star-style restraint is depicted in FIGS. 1-9 of the attached drawings. In conducting tests of vehicle restraints in light of the new NHTSA standards, we have determined that the present design of a Star-style restraint makes the restraint susceptible to the dangerous condition of allowing a vehicle with what appears to be a properly restrained ICC bar to pull away and separate from the loading dock under certain commonly-occurring circumstances. As will be described in greater detail in the specification to follow, we have determined that the design of a Star-style unit allows the restraining member to be forced downward by a departing ICC bar to a position where it fails to restrain the ICC bar and the vehicle can drive or otherwise move away from the loading dock.
Accordingly, an object of the present invention is to provide improvements and modifications to a Star-style unit and other similar restraints that prevent such restraint failure. Beyond that, however, it is also an object of the present invention to generally provide safer vehicle restraints that maintain engagement with a vehicle ICC bar, particularly during pull-aways. It is a further object of the invention to provide this enhanced safety to vehicle restraints without otherwise impeding the normal operation of such restraints. It should be noted that while the inventions disclosed herein may be useful in enhancing the operation of given vehicle restraints, some restraints will not require use of the invention as other features of those restraints provide the desired functionality. Further still, certain restraints may have design characteristics that prevent incorporation of the inventive concepts of this application while still allowing the restraint to practically service the varied configurations of ICC bars and trailers.
In accordance with these and other objects of the invention, there is provided improved components for vehicle restraints as well as improved restraints, which are intended to eliminate or minimize the causes of uncontrolled separation attributable to Star-style and similar units. In addition to providing improved restraint components and restraints that avoid these causes, there is also provided specific improvements to Star-style units or similar restraints, the improvements being intended to prevent or minimize the possibility for uncontrolled separation of a parked, restrained vehicle from a loading dock.
The improved restraints, restraint components and the specific improvements to the Star-style restraints fall into two general categories. In the first category, improvements to the design of the barrier portion or head of the restraining member are provided. The barrier portion or head is the portion of the restraining member behind which the ICC bar is intended to be captured. The new restraining member designs and the Star-style head improvements prevent what is believed to be the primary factors contributing to Star-style units being forced downward and out of restraining engagement by a departing ICC bar. The other broad category of restraints, restraint components and specific improvements to the Star-style restraint are directed to locking the restraining member of a restraint into a given vertical position for a pull away by the parked vehicle. The lock does not impede normal operation of the restraint, but is only activated during a pull away to prevent failure of the restraint.
The embodiments of the invention will be described herein in reference to the appended drawings, wherein: